Axially movable electrode holder for use in electric steel production

Abstract

An axially movable electrode holder of metal, particularly copper or copper base alloy, for active parts of consumable or slowly consumable material, which are attachable by means a threaded nipple or a similar means. The electrode holder comprises a cooling unit with a supply and a return duct, and has at least partly, preferably its lower region, a protective coating and a contact arrangement on its sheath area by which the electrode holder may be connected to a current supply. The electrode holder further comprises a number of removably mounted electrical and/or mechanical contact moldings of pressure-resistant material extending over a length of the electrode holder which corresponds too at least a part of the length of an allowable tip consumption. The electrode holder, which is intended for use in the electric steel production, is characterized by a high reliability in service, good maneuverability, and good electrical properties.

We claim: 
     
       1. In an axially movable metallic electrode holder having a threadable interconnection means for attaching active electrode parts of consumable material to the electrode holder, and a cooling means having a supply and a return coolant conduit pipe, and at least one contact means by which the electrode holder is mechanically engaged by clamping jaws and thereby electrically connected to a supply of electrical current, the improvement comprising the contact arrangement having at least an uppermost and a lowermost contact zone of a pressure-resistant material, each contact zone having an axial dimension sufficient to receive the clamping jaws, whereby a distance between the uppermost and the lowermost contact zone corresponds to at least a portion of an allowable length of consumption of the active electrode parts. 
     
     
       2. The electrode holder as set forth in claim 1 including a continuous sequence of discreet contact zones between the uppermost and lowermost. 
     
     
       3. The electrode holder as set forth in any one of claims 1 and 2 wherein said contact zones constitute rings of highly conductive material resting against the metal sheath area. 
     
     
       4. The electrode holder as set forth in claim 3 wherein said contact zones are formed from at least one segment. 
     
     
       5. The electrode holder as set forth in claim 4 wherein said contact zones are made of highly conductive graphite. 
     
     
       6. The electrode holder as set forth in claim 5 wherein said contact zones are arranged to allow the electrical current to be supplied over a zone encompassing approximately the upper third of the electrode holder. 
     
     
       7. The electrode holder as set forth in claim 5 wherein said contact zones are arranged to allow the electrical current to be supplied over a zone encompassing approximately the upper half of the electrode holder. 
     
     
       8. The electrode holder as set forth in claim 1 including means for fastening said contact segments to the electrode, the fastening means including conductive coverings. 
     
     
       9. The electrode holder as set forth in claim 8, the electrode including an outer sheath having junctions between the sheath and the segments forming the contact zones, the function being filled with a mastic. 
     
     
       10. The electrode holder as set forth in claims 1 or 3, the contact segments having each a central point the points being axially aligned, and to a distance of approximately 0.5 m to 0.9 m each from the other. 
     
     
       11. The electrode holder as set forth in claim 10, wherein said contact zones encompass approximately 0.6 m to 2.0 m linearly of the upper part of the electrode holder. 
     
     
       12. The electrode holder as set forth in claims 1 or 3, at least in the area of the contact zones including internal, mechanically resistant bracings configured to counteract a mechanical deformation of the electrode holder by the fastening means and the contact means. 
     
     
       13. The electrode holder as set forth in claim 12 wherein the bracings are fastened to the interal cooling conduit pipes. 
     
     
       14. The electrode holder as set forth in claims 1 or 3 including a plurality of high-temperature resistant protective segments arranged surrounding portions of said electrode holder not engaged by the contact means. 
     
     
       15. The electrode holder as set forth in claim 14 wherein said protective segments are made of electrically conductive material. 
     
     
       16. The electrode holder as set forth in claim 15 wherein at least a lowermost protective segment upon the electrode holder is secured by a fastener to the electrode holder. 
     
     
       17. The electrode holder as set forth in claim 15 a high-temperature resistant, intermediate material being placed between the protective segments and the electric holder. 
     
     
       18. The electrode holder as set forth in claim 17 wherein the intermediate material comprises one of graphite foil, graphite fleece, ceramic paper and copper strand. 
     
     
       19. The electrode holder as set forth in claim 14 wherein said contact zones and said protective segments are essentially flush.